Method, system, and device for decontaminating polluted combustion gas using volcanic rock

ABSTRACT

The present disclosure encompasses methods and systems for decontaminating polluted gas using heated volcanic rock.

FIELD OF THE INVENTION

The invention encompasses methods and systems for decontaminating a polluted combustion gas using heated volcanic rock.

BACKGROUND OF THE INVENTION

It is widely accepted that the burning of fossil fuels and waste is contributing to global warming and to the pollution of the planet. Additionally, combustion gases generated by the burning of these fuels contain many components that are thought to be hazardous to human, plant, and animal health. Many solutions at reducing the emission of pollutants and minimizing the impact on global warming have been proposed, but many are difficult or expensive to implement or detract from the overall efficiency of the fuel being burned.

The present disclosure is related to the filtration of combustion gases. More particularly, the present disclosure is related to the removal of pollutants from combustion gases. Still more particularly, the present disclosure is related to the use of a widely available natural substance to remove pollutants from combustion gases. Even more particularly, the present disclosure is related to the use of volcanic rock to remove pollutants from combustion gases.

SUMMARY OF THE INVENTION

The present disclosure provides systems, devices, and methods that overcome the problems inherent in the prior art and provides a distinct advance in the state of the art.

In one aspect of the present invention, a device and/or system for removing at least one pollutant from a combustion gas is provided. In general, the device and/or system includes a combustion chamber having an inside and an outside. Such a device and/or system will generally be defined by a container having walls separating the inside from the outside, thereby confining the combustion to the inside of the container. The device and/or system further includes a heat source located in the combustion chamber. When the heat source undergoes combustion, it generates a combustion gas that includes pollutants therein. An exhaust passageway having an entrance inside said combustion chamber and an exit outside said combustion chamber connects the inside of the combustion chamber with the outside of the combustion chamber. Such a passageway effectively provides a passageway for the discharge of the combustion gas from the combustion chamber to the exterior of the device where it can mix with the atmosphere surrounding the device. The device and/or system further includes a quantity of volcanic rock inside the combustion chamber. In preferred forms, the volcanic rock is positioned between said heat source and the exhaust passageway. By positioning the volcanic rock in such a fashion, the gases formed during combustion contact the volcanic rock and interfere with their unobstructed passage to the exterior of the device. By contacting the volcanic rock, at least 1, preferably at least 2, even more preferably at least 3, still more preferably at least 4, more preferably at least 5, even more preferably at least 6, still more preferably at least 7, 8, 9, 10, or more, and preferably all of the pollutants in the combustion gas are removed. Preferably the combustion gas contacts said volcanic rock prior to entering said exhaust passageway thereby removing at least one pollutant from said combustion gas prior to entering said exhaust passageway and exiting the inside of said combustion chamber. In terms of the percentage of pollutants removed, preferably at least 10%, more preferably at least 20%, still more preferably at least 30%, even more preferably at least 40%, more preferably at least 50%, still more preferably at least 60%, even more preferably at least 70%, more preferably at least 80%, still more preferably at least 90%, even more preferably at least 95%, and most preferably 100% of the pollutants are removed from the combustion gas by contacting the volcanic rock.

Pollutants removable by the volcanic rock are any pollutant typically formed by combustion. Preferably, the pollutants are selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof.

The combustion chamber can be located in any device or system that conventionally includes a combustion chamber. Preferred devices are selected from the group consisting of a furnace, stove, incinerator, boiler, automotive exhaust system, and combinations thereof.

The combustion chamber heat source can use any material for fuel, whether such material is a conventional fuel or not. The only requirement is that it must be able to be burned. Preferably, the heat source uses a fuel selected from the group consisting of liquefied fuel, gaseous fuel, contaminating fuel, wood, charcoal, peat, coal, hexamine fuel tablets, pellets made from wood, corn, wheat, rye, or other plants, and combinations thereof. Preferred liquefied fuels are selected from the group consisting of hydrogen, ethanol, fuel oil, biodiesel, gasoline, kerosene, diesel, liquefied natural gas, liquefied propane, and combinations thereof. Preferred gaseous fuels are selected from the group consisting of methane, propane, hydrogen, carbon monoxide, and combinations thereof. Preferred contaminating fuels are selected from the group consisting of waste material used in incinerators, waste material used in waste to energy systems, rubber tires, asphalt shingles, plastics, styrenes, styrofoams, paper, indiscriminate household or domestic waste, agricultural waste, and combinations thereof.

It is understood that the volcanic rock can be in any form. Preferably the volcanic rock is in a form selected from the group consisting of chunks, blocks, and combinations thereof. Preferably, when the volcanic rock is in chunks, it ranges in size from pebbles to boulders. Preferred pebble diameters range from about 0.1 cm to about 90 cm, with any range therein being possible. For example, pebbles could range in size from about 0.1 cm to about 45 cm, 45 cm to 80 cm, 1 cm to about 10 cm, 2 cm to about 20 cm, 5 cm to about 30 cm, 5 cm to about 15 cm, 1 cm to about 5 cm, 2.5 cm to about 7.5 cm, and the like. Boulders are generally larger in diameter than pebbles and have diameters larger than 90 cm. As with pebble sizes, boulder sizes can vary greatly and can encompass any range of diameters between 90 cm and 450 cm and larger. Preferred boulders have diameters between about 90 cm and 250 cm, more preferably between 120 cm and about 200 cm. When blocks are used, they can have a depth ranging from about 1 inch to 15 feet or more. In preferred forms, the depth is 1 inch to about 6 feet. Other ranges are possible and have significant utility. For example, the depth can be between 3 inches and 3 feet, between 6 inches and 4 feet, between 4 inches and 5 feet, between 1 inch and 1 foot, between 3 inches and 9 inches, between 3 inches and 6 inches, and the like.

The quantity of volcanic rock in the combustion chamber must be sufficient to provide a large enough surface area to remove the pollutants from the combustion gas. In preferred forms, the volcanic rock occupies from about ½ to 1/40^(th) of the volume of said combustion chamber. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the combustion chamber.

In preferred forms, the quantity of volcanic rock is positioned in said combustion chamber such that there is an empty space or void between the top of said quantity of volcanic rocks and the entrance to the exhaust passageway.

In other preferred forms, the present invention includes a cleaning mechanism for cleaning the volcanic rocks used therein. The cleaning mechanism can be anything that can remove any debris from the volcanic rock. Such debris can include any of the pollutants listed above or the products of their breakdown from the heat in the combustion chamber. Preferred cleaning mechanisms are selected from the group consisting of an agitator that shakes the volcanic rock, a liquid applicator that rinses said volcanic rocks with a liquid, and combinations thereof. In other preferred forms, the device can include a door providing access from the exterior of the device to the interior of the device. This door can be used to remove the volcanic rock from inside the device such that it can be replaced or cleaned while outside the device.

The present disclosure also provides a system and/or device for removing at least one pollutant from the exhaust of an internal combustion engine. Generally, the system or device comprises an internal combustion engine having a combustion chamber therein. The combustion chamber includes a fuel burning area which generates exhaust when a fuel is being burned. An exhaust port having a first end in proximity to the fuel burning area and a second end in communication with the first end, wherein the second end is in proximity to the environment outside said internal combustion engine is also included. The exhaust port is used to vent the combustion gas generated from the burning of the fuel to the outside. A quantity of volcanic rock is preferably disposed between the fuel burning area and the second end of the exhaust port. Thus, the combustion gas is forced to contact the volcanic rock prior to exiting the system or device. In preferred forms, the system or device further includes a canister in communication with the exhaust port. The canister can be placed immediately after the combustion chamber, or anywhere between the combustion chamber and the second end of the exhaust port. Preferably, the canister has a diameter that is larger or greater than the diameter of the exhaust port. Such a canister is a preferred location for the placement of volcanic rock. In some embodiments, the volcanic rock is disposed before the first end of said exhaust port. In other embodiments, the volcanic rock is placed between the first end of the exhaust port and the second end of the exhaust port.

As with the other systems and devices disclosed herein, the system or device for removing at least one pollutant from the exhaust of an internal combustion engine removes pollutants from the combustion gas. By contacting the volcanic rock, at least 1, preferably at least 2, even more preferably at least 3, still more preferably at least 4, more preferably at least 5, even more preferably at least 6, still more preferably at least 7, 8, 9, 10, or more, and preferably all of the pollutants in the combustion gas are removed. Preferably the combustion gas contacts said volcanic rock prior to exiting the exhaust passageway thereby removing at least one pollutant from said combustion gas prior to exiting to the outside air. In terms of the percentage of pollutants removed, preferably at least 10%, more preferably at least 20%, still more preferably at least 30%, even more preferably at least 40%, more preferably at least 50%, still more preferably at least 60%, even more preferably at least 70%, more preferably at least 80%, still more preferably at least 90%, even more preferably at least 95%, and most preferably 100% of the pollutants are removed from the combustion gas by contacting the volcanic rock. Some preferred pollutants are selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof.

The internal combustion engine can use any fuel utilized to power such engines. Preferably, the fuel is selected from the group consisting of liquefied fuel and gaseous fuel. Preferred liquefied fuels are selected from the group consisting of hydrogen, ethanol, fuel oil, biodiesel, gasoline, kerosene, diesel, liquefied natural gas, liquefied propane, and combinations thereof. Preferred gaseous fuels are selected from the group consisting of methane, propane, hydrogen, carbon monoxide, and combinations thereof.

Similar to the other systems and devices described herein, the volcanic rock used to remove pollutants from the exhaust of an internal combustion engine can be in any size, shape, or form. Preferred forms are selected from the group consisting of chunks (or aggregate), blocks, and combinations thereof. Preferably, when the volcanic rock is in chunks, it is in the size of pebbles. Preferred pebble diameters range from about 0.1 cm to about 40 cm, with any range therein being possible. For example, pebbles could range in size from about 0.1 cm to about 35 cm, 1 cm to 30 cm, 1 cm to about 10 cm, 2 cm to about 20 cm, 5 cm to about 30 cm, 5 cm to about 15 cm, 1 cm to about 5 cm, 2.5 cm to about 7.5 cm, 1 cm to about 15 cm, and the like. When blocks are used, they will be sized to fit the canister or exhaust port dimensions. Preferred sizes of blocks will have a depth ranging from about 1 inch to 15 inches or more. In preferred forms, the depth is 1 inch to about 6 inches. Other ranges are possible and have significant utility. For example, the depth can be between 3 inches and 1 foot, between 1 inch and 4 inches, between 3 inches and 5 inches, between 1 inch and 1 foot, between 3 inches and 9 inches, between 3 inches and 6 inches, and the like.

The quantity of volcanic rock in the canister or exhaust port must be sufficient to provide a large enough surface area to remove the pollutants from the combustion gas. In preferred forms, the volcanic rock occupies from about ½ to 1/40^(th) of the volume of the canister or port. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the canister or port.

In other preferred forms, the present invention includes a cleaning mechanism for cleaning the volcanic rocks used therein. The cleaning mechanism can be anything that can remove any debris from the volcanic rock. Such debris can include any of the pollutants listed above or the products of their breakdown from the heat in the combustion chamber. Preferred cleaning mechanisms are selected from the group consisting of an agitator that shakes the volcanic rock, a liquid applicator that rinses said volcanic rocks with a liquid, and combinations thereof. In other preferred forms, the canister or port can include a door providing access from the exterior of the device to the interior of the device. This door can be used to remove the volcanic rock from inside the device such that it can be replaced or cleaned while outside the device.

The present disclosure also provides a method of decontaminating polluted combustion gas. The method generally includes the step of contacting the polluted combustion gas with volcanic rock for a time sufficient to remove at least one pollutant from the polluted combustion gas. Preferably any pollutant can be removed or filtered using the described method. By contacting the volcanic rock, at least 1, preferably at least 2, even more preferably at least 3, still more preferably at least 4, more preferably at least 5, even more preferably at least 6, still more preferably at least 7, 8, 9, 10, or more, and preferably all of the pollutants in the combustion gas are removed. Preferably the combustion gas contacts the volcanic rock prior to exiting to the outside air. This can be done inside of a combustion chamber or within an exhaust system. In terms of the percentage of pollutants removed, preferably at least 10%, more preferably at least 20%, still more preferably at least 30%, even more preferably at least 40%, more preferably at least 50%, still more preferably at least 60%, even more preferably at least 70%, more preferably at least 80%, still more preferably at least 90%, even more preferably at least 95%, and most preferably 100% of the pollutants are removed from the combustion gas by contacting the volcanic rock. Preferred pollutants are selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof. Preferred devices on which to practice the disclosed method are any devices that include combustion. Particularly preferred devices include those selected from the group consisting of a furnace, stove, incinerator, boiler, internal combustion engine exhaust system, and combinations thereof.

As with the systems and devices disclosed herein, the disclosed method can work with any material capable of being burned, especially those capable of being burned in one of the preferred devices. In preferred forms, the polluted combustion gas is formed from the combustion of a fuel selected from the group consisting of liquefied fuel, gaseous fuel, contaminating fuel, wood, charcoal, peat, coal, hexamine fuel tablets, pellets made from wood, corn, wheat, rye, or other plants, and combinations thereof. Preferred liquefied fuels are selected from the group consisting of hydrogen, ethanol, fuel oil, biodiesel, gasoline, kerosene, diesel, liquefied natural gas, liquefied propane, and combinations thereof. Preferred gaseous fuels are selected from the group consisting of methane, propane, hydrogen, carbon monoxide, and combinations thereof. Preferred contaminating fuels are selected from the group consisting of waste material used in incinerators, waste material used in waste to energy systems, rubber tires, asphalt shingles, plastics, styrenes, styrofoams, paper, indiscriminate household or domestic waste, agricultural waste, and combinations thereof.

Any form of volcanic rock can be useful for the disclosed method. Preferred forms include chunks, blocks, and combinations thereof. Preferably, when the volcanic rock is in chunks, it ranges in size from pebbles to boulders. Preferred pebble diameters range from about 0.1 cm to about 90 cm, with any range therein being possible. For example, pebbles could range in size from about 0.1 cm to about 45 cm, 45 cm to 80 cm, 1 cm to about 10 cm, 2 cm to about 20 cm, 5 cm to about 30 cm, 5 cm to about 15 cm, 1 cm to about 5 cm, 2.5 cm to about 7.5 cm, and the like. Boulders are generally larger in diameter than pebbles and have diameters larger than 90 cm. As with pebble sizes, boulder sizes can vary greatly and can encompass any range of diameters between 90 cm and 450 cm and larger. Preferred boulders have diameters between about 90 cm and 250 cm, more preferably between 120 cm and about 200 cm. When blocks are used, they can have a depth ranging from about 1 inch to 15 feet or more. In preferred forms, the depth is 1 inch to about 6 feet. Other ranges are possible and have significant utility. For example, the depth can be between 3 inches and 3 feet, between 6 inches and 4 feet, between 4 inches and 5 feet, between 1 inch and 1 foot, between 3 inches and 9 inches, between 3 inches and 6 inches, and the like.

The quantity of volcanic rock in the combustion chamber or exhaust system must be sufficient to provide a large enough surface area to remove the pollutants from the combustion gas. In preferred forms, the volcanic rock occupies from about ½ to 1/40^(th) of the volume of said combustion chamber or exhaust system. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the combustion chamber or exhaust system.

In some preferred embodiments of the disclosed method, the method will also include a step of cleaning the volcanic rock. Any method of cleaning can be used. Preferred methods include agitating the volcanic rock, rinsing said volcanic rock using a liquid applicator, and combinations thereof. When the volcanic rock is located in a combustion chamber, such cleaning can be effected in the combustion chamber. When it is located in an exhaust system, cleaning can be effected within that system. Alternatively, the volcanic rock can be removed from any of the systems or devices and cleaned or replaced.

In other preferred forms applicable to all of the devices, systems, and methods disclosed herein, the amount of volcanic rock will not be so much as to stop the flow of combustion gas from a combustion chamber to the exhaust port or exit passageway of the device or system. Such an amount could “choke” the system and interfere with the combustion process. It is desired to have a flow of air through the volcanic rock and the rate of flow will be such that the combustion gas has an opportunity to contact the volcanic rock and have the pollutants therein removed. In some preferred embodiments, the systems or devices will include a vacuum on the side of the volcanic rock that includes the exhaust exit. The force of the vacuum will be sufficient to keep a desired rate of flow through the volcanic rock. Some of the flow may dissolve through the volcanic rock while other portions of the flow may pass through pores, fissures, gaps, and the like.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front facing view of a traditional wood stove used for heating purposes with portions of the interior shown;

FIG. 2 is an orthogonal view of a square slab of volcanic rock;

FIG. 3 is an orthogonal view of a cylindrical slab of volcanic rock;

FIG. 4 is a cross-sectional view of a diversity of conduits for gaseous transmission through slabs of volcanic rock:

FIG. 4A illustrates a diagonal conduit system through which exhaust gases flow from the combustion chamber and pass through said slab to the exhaust port of device. The conduit placement should be such that a significant surface area of volcanic rock exists between conduits and the periphery of volcanic rock slab;

FIG. 4B illustrates a vertical conduit system through which the exhaust gases flow from the combustion chamber and pass through said slab to the exhaust port of device. The conduit placement should be such that a significant surface area of volcanic rock exists between conduits and the periphery of volcanic rock slab;

FIG. 4C illustrates a branched conduit system through which the exhaust gases flow from the combustion chamber and pass through said slab to the exhaust port of device. The conduit placement should be such that a significant surface area of volcanic rock exists between conduits and the periphery of volcanic rock slab;

FIG. 5 is a cutout diagram of a catalytic converter-type canister used for decontaminating exhaust gas from an internal combustion engine;

FIG. 6 is a schematic drawing of a waste-to-energy incinerator with combustion gases following the upper set of arrows and ash following the lower set of arrows;

FIG. 7 is cross section of a schematic drawing of a tube-in-water boiler;

FIG. 8 is a schematic drawing of a slab or block of volcanic rock having a plurality of conduits therethrough;

FIG. 9 is a schematic drawing of a pile of volcanic rock piled on top of a tube;

FIG. 10 is a schematic drawing of a boiler having tubing wrapped around the exterior of the boiler;

FIG. 11 is a scan of flue gas resulting from a mixed fuel fire that included tires and plastics as a fuel source; and

FIG. 12 is a scan of flue gas resulting from a wood fire.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, “volcanic rock” refers to any rock formed from magma that has erupted from a volcano. Preferably, volcanic rock in the present disclosure is vesicular volcanic rock. Vesicular volcanic rock is created when super-heated, highly pressurized rock is violently ejected from a volcano to produce an unusual foamy configuration because of simultaneous rapid cooling and rapid depressurization. Depressurization creates bubbles (vesicles) by lowering solubility of gases that are dissolved in lava, causing gases to rapidly exsolve. Simultaneous cooling and depressurization freezes the bubbles in the matrix. Non limiting examples of vesicular volcanic rock include pumice and scoria. In some embodiments, a volcanic rock of the disclosure is pumice. In other embodiments, a volcanic rock of the disclosure is scoria. Pumice is highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles and thicker vesicle walls and being dark colored and denser.

The physical and chemical characteristics of volcanic rock can and will vary depending on the origin of the rock. For instance, physical characteristics may include the density and size of vesicles in volcanic rock. Additionally, chemical composition of volcanic rock may vary depending on the origin of the quarried rock. In general, a physical characteristic that may be advantageous for the use of volcanic rock to decontaminate polluted gas may include increased surface area resulting from a higher number of vesicles. Other chemical and physical characteristics of volcanic rock that may influence efficiency of decontamination can and will vary and may be determined experimentally for its intended use.

It was discovered that volcanic rock can efficiently decontaminate a polluted combustion gas. Further, as the volcanic rock was heated, its capability for decontaminating a polluted combustion gas increased. As such, the present disclosure describes the use of heated volcanic rock and devices using heated volcanic rock to remove contaminants from a polluted gas. A method of the disclosure comprises contacting a polluted combustion gas with heated volcanic rock. While not wishing to be bound by theory, it is believed that heated volcanic rock, when used in a method, system, and device of the present disclosure, may act as a naturally occurring catalyst capable of decontaminating a polluted gas. Advantageously, volcanic rock is plentiful, inexpensive, and can withstand elevated temperatures for extended periods of time without loss of integrity. Additionally, it was discovered that heated volcanic rock, but not unheated volcanic rock is resistant to clogging, and is therefore self-regenerative, and requires minimal maintenance and cleaning for continued efficient function even for extended periods of time.

I. Method for Decontaminating a Polluted Gas

One aspect of the invention encompasses a method of using heated volcanic rock to decontaminate a polluted combustion gas. A method of the present disclosure may be used to decontaminate combustion gas from any combustion device. Non limiting examples of combustion devices that may be used with a system of the disclosure may include fuel-burning power generating stations, furnaces, boilers, stoves, hog-fuel boilers, ship boilers, waste incinerators, turboprop engines, and gas, or diesel-burning engines. Advantageously, it was discovered that volcanic rock efficiently decontaminates a polluted gas resulting from combustion of fuel known to generate large amounts of pollutants, including particulates.

Volcanic rock may be of any size or shape, provided the size and shape of the rock provides a sufficiently high surface area for contacting and decontaminating a polluted gas. Volcanic rock may be a solid block of quarried volcanic rock. Such a block of volcanic rock may be shaped for its intended use (FIG. 2, 3). Additionally, a block of volcanic rock may have conduits for channeling contaminated gas (FIG. 2, 3, 4). Volcanic rock may also be ground and shaped with or without a binder into a multitude of sizes and shapes that may be appropriate for its intended use. Methods of shaping ground rock are known in the art.

Alternatively, volcanic rock of the disclosure may be an aggregate of smaller pieces of volcanic rock. The size of volcanic rock aggregate can and will vary depending on the intended use of the volcanic rock and may be determined experimentally. An aggregate of volcanic rock increases the surface area of the rock allowing for a more efficient contact and catalysis of pollutants for decontamination. For example, volcanic rock pebbles could range in size from about 0.1 cm to about 45 cm, 45 cm to 80 cm, 1 cm to about 10 cm, 2 cm to about 20 cm, 5 cm to about 30 cm, 5 cm to about 15 cm, 1 cm to about 5 cm, 2.5 cm to about 7.5 cm, and the like. Boulders are generally larger in diameter than pebbles and have diameters larger than 90 cm. As with pebble sizes, boulder sizes can vary greatly and can encompass any range of diameters between 90 cm and 450 cm and larger. Preferred boulders have diameters between about 90 cm and 250 cm, more preferably between 120 cm and about 200 cm. When blocks are used, they can have a depth ranging from about 1 inch to 15 feet or more. In preferred forms, the depth is 1 inch to about 6 feet. Other ranges are possible and have significant utility. For example, the depth can be between 3 inches and 3 feet, between 6 inches and 4 feet, between 4 inches and 5 feet, between 1 inch and 1 foot, between 3 inches and 9 inches, between 3 inches and 6 inches, and the like.

The temperature of heated volcanic rock can and will vary depending on the surface area of volcanic rock, the duration of exposure of the contaminants to heated rock, the pollutants in a polluted combustion gas contacting the heated rock, and a combination thereof. As such, volcanic rock at higher temperatures may be used for decontaminating a gas when the gas is contacted with heated rock having a smaller surface area, or for a shorter duration of time. Conversely, lower temperatures may be used for decontaminating a gas when the gas is contacted with heated rock having a larger surface area, or for a longer duration of time. Volcanic rock at higher temperatures may be used for decontaminating pollutants resistant to breakdown when compared to lower temperatures that may be needed for pollutants that are less resistant to breakdown. Similarly, a longer duration of exposure may be used for decontaminating pollutants resistant to breakdown when compared to a shorter duration of exposure that may be needed for pollutants that are less resistant to breakdown. Temperatures of heated volcanic rock may be about 100 to about 500° C., about 400 to about 1000° C., or about 900 to about 2000° C. or more.

Volcanic rock may be used to decontaminate pollutants from combustion of any fuel. Non-limiting examples of a fuel include solid fuel such as wood, charcoal, peat, coal, hexamine fuel tablets, and pellets made from wood, corn, wheat, rye and other grains; a liquid fuel such as liquefied hydrogen, ethanol, fuel oil, and biodiesel, or any other petroleum product such as gasoline, kerosene, diesel, liquefied natural gas, and liquified propane; or a gaseous fuel such as methane, propane, hydrogen, carbon monoxide, or mixtures thereof. Volcanic rock may also be used to decontaminate pollutants from combustion of contaminating fuel known to generate large amounts of pollutants, including particulates. A contaminating fuel may include, in addition to the fuels described above, non-traditional fuel sources such as waste material used in incinerators and waste-to-energy systems. Non limiting examples of waste material that generate large amounts of pollutants when burned include indiscriminate domestic or agricultural waste, rubber tires, asphalt shingles, plastics, or other petroleum products that can produce dense black smoke. As such, in a preferred embodiment, a method of the invention may be used to decontaminate a polluted combustion gas from a combustion device known to generate large amounts of pollutants, including particulates.

The composition of pollutants generated by combustion of a fuel that may be decontaminated using methods and devices of the present disclosure can and will vary depending on the fuel and the combustion conditions. For instance, ideal combustion conditions result in complete combustion of fuels and may generate fewer pollutants than fuels burned under less than ideal conditions. In general, a combustion gas may comprise nitrogen derived from the air, carbon dioxide (CO₂), and water vapor, as well as excess oxygen (also derived from the combustion air). Other pollutants may comprise carbon monoxide (CO), various hydrocarbons (CxHy) from unburned fuel, nitrogen oxides (NOx), nitric acid, styrene gas, mercury, polychlorinated biphenyls, ozone (O3), sulfur oxides, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, and particulate matter such as soot (impure carbon particles), diesel particulate matter (DPM), heavy metals, dioxins, furans, sulfur dioxide, methane, hydrochloric acid, benzo(a)pyrene, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitric acid, diesel particulate matter, methane, and combinations thereof.

By contacting the heated volcanic rock removes at least 1 to more than 1000, and preferably all of the pollutants in the combustion gas are removed. Preferably, at least 1, preferably at least 2, even more preferably at least 3, still more preferably at least 4, more preferably at least 5, even more preferably at least 6, still more preferably at least 7, 8, 9, 10, or more, and preferably all of the pollutants in the combustion gas are removed. In terms of the percentage of pollutants removed, preferably at least 10%, more preferably at least 20%, still more preferably at least 30%, even more preferably at least 40%, more preferably at least 50%, still more preferably at least 60%, even more preferably at least 70%, more preferably at least 80%, still more preferably at least 90%, even more preferably at least 95%, and most preferably 100% of the pollutants are removed from the combustion gas by contacting the volcanic rock.

II. System for Decontaminating a Polluted Combustion Gas

Another aspect of the invention encompasses a system for decontaminating a polluted combustion gas using heated volcanic rock. A system of the present disclosure comprises volcanic rock, means for heating the volcanic rock, and means for contacting polluted combustion gas with the heated volcanic rock.

Volcanic rock may be as described in Section I. Any means for heating volcanic rock may be used. Non-limiting examples of heating means that may be used with a system of the present disclosure include an electrical heating element disposed within volcanic rock, and a flame disposed in close proximity to volcanic rock. Preferably, a means for heating volcanic rock comprises placing the volcanic rock in proximity to the heat source from combustion. As such, volcanic rock may be disposed within a combustion chamber, or may be disposed in a compartment connected to, and at any distance from the combustion chamber. The distance of the volcanic rock from the heat source can and will vary depending on the combustion system and the intensity of heat of combustion, and may be determined experimentally for each combustion system. Preferable means for contacting heated volcanic rock with a combustion gas may comprise disposing volcanic rock at the point of gas exhaust, thereby ensuring contact of the combustion gas with heated volcanic rock during exhaust.

A preferable system for decontaminating a polluted combustion gas of the present disclosure comprises volcanic rock disposed at the point of exhaust, in proximity to a heat source from combustion. A more preferred system comprises volcanic rock disposed in the combustion chamber of a combustion system at the point of exhaust. The quantity of volcanic rock in a system of the present disclosure must be sufficient to provide a large enough surface area to remove the pollutants from the combustion gas. In preferred forms, the volcanic rock occupies from about ½ to 1/40^(th) of the volume of said combustion chamber. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the combustion chamber.

In preferred forms, when volcanic rock is disposed in a combustion chamber, the quantity of volcanic rock is positioned in said combustion chamber such that there is an empty space or void between the top of said quantity of volcanic rocks and the entrance to the exhaust passageway. Alternatively, the quantity of volcanic rock in said combustion chamber is positioned such that there is no empty space or void between the top of said quantity of volcanic rocks and the entrance to the exhaust passageway.

In a system of the present disclosure, efficiency of decontamination of a polluted gas may be controlled by controlling the duration of contact of contaminated gas with the heated volcanic rock. Duration of contact can and will vary depending on the combustion system and the fuel used in the combustion system, and may be determined experimentally for each system. For instance the duration of contact of contaminated gas with the heated volcanic rock may be about 1 millisecond to about 0.5 second, about 0.4 second to about 1 second, about 0.9 second to about 5 seconds, about 4 seconds to about 10 seconds, about 9 seconds to about 30 seconds, or about 20 seconds to about 1 minute or longer.

Duration of contact of combustion gas with heated volcanic rock may be controlled by controlling flow speed of exhaust gas from the combustion chamber and through the volcanic rock, and/or the depth of volcanic rock material available for contacting combustion exhaust. Means for controlling flow speed of exhaust gas from a combustion chamber are known in the art. Non-limiting examples of means for controlling flow speed of exhaust may include valve means, or fan means. Preferably, means for controlling flow speed of exhaust through heated volcanic rock comprises disposing volcanic rock at a point of gas exhaust to obstruct and control flow of exhaust. Depth of volcanic material can and will be determined experimentally for the intended use of a system.

Controlling flow speed of exhaust gas may also be used to control residence time of contaminated gas in a combustion chamber. Controlling residence time of contaminated gas in a combustion chamber controls exposure of contaminants in combustion gas to heat from combustion, thereby enhancing decontamination of the gas. For instance, when decontaminating a polluted gas comprising particulate matter, increasing residence time in a combustion chamber may provide sufficient time for particulates to burn completely into ash, thereby removing particulates from a contaminated gas. Advantageously, when disposed at the point of gas exhaust in a combustion system, insulating properties of volcanic rock also confine heat energy in the combustion chamber for more efficient harvesting of heat energy from the combustion system.

A system of the present disclosure may be used alone, or in combination with other conventional filtering systems. For instance, a system of the present disclosure may be used with a chlorine gas scrubber for precipitation of chlorine gas for reuse and recycling. Other accessory filtering systems that may be used in combination with a system of the present disclosure may include CO₂ scrubbers, traditional barrier-type filters, thermal oxidizing catalyst systems, water or other liquid misters, ceramic filters, and the like. Further, the systems and devices of the present disclosure can include air sampling devices to monitor the discharge of combustion gases into the atmosphere. If too many pollutants are making it through the system or device without being removed by the volcanic rock, these sampling devices can be used to adjust the parameters responsible for removing the pollutants. For example, if a vacuum or other form of air flow is being used, it may be adjusted. Alternatively, the volcanic rock can be exchanged or cleaned, or even inspected for faults or cracks through which combustion gas is escaping prior to contacting the volcanic rock for a time sufficient to remove the pollutants from the gas.

(a) Wood-Burning Stove

In preferred embodiments, a system of the present disclosure may be used to decontaminate a combustion gas from a wood-burning stove. A wood-burning stove may be a Franklin stove, a fireplace insert, a down draft gasification stove, a cross draft gasification stove, a chimenea, or a traditional wood-burning stove. A wood-burning stove in accordance with the present invention may use any conventional fuel source including firewood, wood pellets, coal, or peat, as well as any other material that is capable of undergoing combustion in a wood burning stoves including unconventional fuel sources such as indiscriminate trash, tires, plastics, styrofoams, and other materials described herein. Preferably, a wood-burning stove 10 is a traditional firewood-burning stove as depicted in FIG. 1, generally comprising a combustion chamber 12 with a fuel inlet 14 and an air inlet 16, and an outlet for exhaust 18. Exhaust outlet 18 includes an entrance 19, disposed within stove 10, and an exit 21 positioned outside the stove 10. A passageway connects the entrance 19 with the exit 21. Fuel burns within the combustion chamber 12, thereby producing combustion gas (or exhaust) which contacts the volcanic rock 20 within the combustion chamber before entering the entrance 19 and exiting the stove 10 through the exit 21. The wood stove 10 further comprises a fuel loading door 42 including a handle 44 and hinges 46 and an ash removal door 48, which also includes a handle 50 and hinges 52. Legs 54 elevate and support the wood burning stove 10.

When used in a wood-burning stove, volcanic rock 20 is preferably positioned in the combustion chamber 12 between the burning fuel and the exhaust inlet. Alternatively or additionally, volcanic rock can also be disposed in the passageway between the entrance 19 and the exit 21. Preferably, the volcanic rock is supported by a grate 22, which can be a conventional perforated steel tray or the like. Thus, prior to exiting the stove 10 through the exhaust outlet 18, the combustion gas or exhaust flows through or is forced to flow through heated volcanic rock 20. By flowing through the volcanic rock 20, the combustion gas is decontaminated and pollutants are removed from the gas by the volcanic rock 20. Forcing exhaust gas to flow through heated volcanic rock 20 may also control the flow of exhaust and the residence time of contaminated gas in a combustion chamber for efficient decontamination of exhaust and particulate matter. Preferably, volcanic rock 20 is disposed in a combustion chamber 12 of a wood-burning stove 10 suspended at a predetermined distance above the fire for heating volcanic rock 20. Disposing volcanic rock 20 in a combustion chamber of a wood burning stove 10 also allows particulates in a combustion gas to contact heated volcanic rock 20, further catalyzing removal of particulates. Volcanic rock 20 may be suspended about 5 to about 100 cm from the fire, preferably about 20 to about 60 cm from the fire, and even more preferably about 40 to about 50 cm from the fire. In preferred forms, the volcanic rock 20 occupies from about ½ to 1/40^(th) of the volume of said combustion chamber. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the combustion. In another preferred form of the invention, the volcanic rock occupies from about ½ to about 1/20^(th) and preferably about ⅓^(rd) to about 1/7^(th) of the volume of said combustion chamber 12. It is understood that the amount of volcanic rock may vary according to the size of the stove and the materials being burned therein. The goal is to have the combustion gas contact the volcanic rock for a time sufficient to remove at least a portion of the pollutants from the combustion gas. In preferred forms, at least 5% of the pollutants, more preferably at least 10%, still more preferably at least 15%, even more preferably at least 20-25%, more preferably at least 25-35%, still more preferably at least 35%, even more preferably at least 35%-40%, more preferably at least 40%, still more preferably at least 40-50%, even more preferably at least 50%, more preferably at least 50-60%, still more preferably at least 60-70%, even more preferably at least 70-80%, more preferably at least 80-90%, still more preferably at least 90-92%, even more preferably at least 92-94%, more preferably at least 94-96%, still more preferably at least 96-98%, even more preferably at least 98-99%, and most preferably at least 100% of the pollutants in the combustion gas are removed prior to exiting the stove.

Preferably, volcanic rock 20 disposed in a combustion chamber 12 is disposed in a plane entirely covering the transverse cross section of a combustion chamber 12, thereby maximizing exposure of combustion gas and particulates in the combustion chamber 12 to heated volcanic rock 20. More preferably, volcanic rock 20 is disposed in a combustion chamber 12 of a wood stove 10 suspended at a predetermined distance above the fire, at or before the point of exhaust of combustion gas. In preferred forms, the quantity of volcanic rock 20 is positioned in said combustion chamber 12 such that there is an empty space 24 or void between the top of said quantity of volcanic rocks 20 and the entrance to the exhaust passageway 19. In a preferred embodiment, volcanic rock 20 in a wood-burning stove 10 may be volcanic rock aggregate of any shape or size and especially of those described herein. In preferred forms for conventional wood stoves 10, volcanic rock aggregate is from about 1 to about 6 cm in diameter. In some preferred forms, the volcanic rock 20 is in the form of a solid block or single piece shaped and sized for a particular application. For example, the volcanic rock 20 can be in the shape of a rectangle, as depicted in FIG. 2, or in a circle as depicted in FIG. 3. When a block or single piece of volcanic rock is provided, it is preferred to have conduits 61 leading from the combustion chamber to the exhaust outlet 18. These conduits 61 permit the combustion gas a passageway through the volcanic rock while still contacting the volcanic rock and thereby have at least some of the pollutants removed therefrom. The conduits 61 are preferably small in diameter and can be straight through the volcanic rock, as depicted in FIGS. 4A and 4B, or branched, as shown in FIG. 4C. The branched form can have multiple branches similar to a capillary system in the human circulatory system. In either form, the combustion gas must contact the volcanic rock 20 such that the pollutants can be removed. Branched passageways are preferred because of their airflow characteristics, which provide the combustion gas a greater opportunity to contact the volcanic rock. If there is not sufficient draw to pull the combustion gas through the volcanic rock, regardless of the form of the volcanic rock, a vacuum can be placed in or near the exhaust outlet in order to produce sufficient draw from the outside air to pull the combustion gas through the volcanic rock. The amount or density of the rock, the number of, shape of, or diameter of passageways therethrough, or force of vacuum pressure can be varied so as to result in optimum residence times and combustion gas decontamination, as described herein. Alternatively, the flow of the combustion gas through the volcanic rock can be aided by an air current moving in the direction of the inlet 19 to the outlet 21.

Volcanic rock 20 may be disposed in a wood stove 10 using a perforated support 22 to allow contact of exhaust gas and contaminants in exhaust gas with heated volcanic rock 20. Any perforated support 24 may be used to suspend volcanic rock 20 in a wood stove 10, provided the support 24 can withstand the elevated temperatures in a combustion chamber 12 of a wood stove 10 and heated volcanic rock 20, and provided the support 24 allows sufficient contact of exhaust gas and contaminants in exhaust gas with heated volcanic rock 20. Non limiting examples of perforated supports include a perforated steel tray 24 and a perforated steel canister.

Although heated volcanic rock 20 is resistant to clogging, and is self-regenerative, in some preferred forms, the present invention includes a cleaning mechanism for cleaning the volcanic rocks used therein. The cleaning mechanism can be anything that can remove any debris from the volcanic rock. Such debris can include any of the pollutants listed above or the products of their breakdown from the heat in the combustion chamber 12. Preferred cleaning mechanisms are selected from the group consisting of an agitator that shakes the volcanic rock, a liquid applicator that rinses said volcanic rocks with a liquid, and combinations thereof. One preferred agitator 26 is shown in FIG. 1 and comprises a handle 28 connected to a rod 29, which is connected to a plurality of arms 30. To activate the agitator 26, a user grasps the handle 28 and moves it in the direction permitted. Some agitators will be designed to permit vertical movement, and others will be designed to permit horizontal movement, and others, such as the one in FIG. 1 will permit angled movement. This movement shakes or agitates the volcanic rock, thereby dislodging the pollutants thereon. A liquid applicator 32 generally comprises a nozzle 34 connected to tubing 36 and further connected to a liquid supply 38. The liquid applicator can be used independently of or in conjunction with an agitator or other cleaning mechanism. Preferably, liquid from a liquid supply 38 travels through the tubing 36 and out of the nozzle and sprays the volcanic rock 20, thereby dislodging the pollutants thereon. In other preferred forms, the device can include a door 40 providing access from the exterior of the device to the interior of the device. This door 40 can be used to facilitate the removal of the volcanic rock 20 from inside the device such that it can be replaced or cleaned while outside the device.

In preferred forms, the wood burning stove of the present invention includes a secondary air system comprising an air inlet 56 inside the stove 10 and in atmospheric communication with air inlet 16, a secondary air pipe 58 in atmospheric communication with air inlet 16 and extending into the combustion chamber 12, and a plurality of holes 60 in the air pipe that bring secondary air into the combustion chamber.

In another preferred embodiment of the present invention, volcanic rock lines the interior of a stove or comprises the outer shell of the stove. Such a use of volcanic rock is in addition to or in place of the volcanic rock 20.

As with the other embodiments disclosed herein, the combustion gases generated by the combustion of the fuel need to contact the volcanic rock for an amount of time sufficient to remove pollutants from the gases. Any pollutant, including but not limited to dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof are removed from the gases. In preferred forms, the volcanic rock removes at least one, preferably at least two, more preferably at least 3, 4, or 5, still more preferably at least 6, 7, 8, 9, or 10, even more preferably at least 11, 12, 13, 14, or 15, and even more preferably 16, 17, 18, 19, or 20, and still more preferably more than 20 pollutants from the combustion gas. Most preferably, all of the pollutants are removed from the combustion gas. Rather than considering the pollutants individually, the volcanic rock can remove at least 10% of the pollutants from the combustion gas. More preferably, the volcanic rock can remove at least 20%, even more preferably at least 30%, still more preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, still more preferably at least 70%, more preferably at least 80%, even more preferably at least 90%, still more preferably at least 95%, more preferably at least 96%, even more preferably at least 98%, still more preferably at least 99%, and most preferably 100% of the pollutants in the combustion gas.

Other embodiments of the present invention include multiple layers of volcanic rock disposed in the combustion chamber. Preferably each layer includes a small gap between it and the next layer. Such a multiple layer system provides an increased opportunity for all of the combustion gases to contact volcanic rock. Again, conduits or passageways can be placed through the volcanic rock in order to facilitate airflow toward the exhaust outlet of the combustion chamber. Such multiple layer systems may find particular utility when using blocks of volcanic rock.

In a still further embodiment of the present invention, the top of the wood stove is either made by or has a layer of stone, preferably soapstone thereon. Such a material is an ideal heat retention device as well as being aesthetically pleasing. Due to the inherent fault lines in stone and soapstone, it is preferred to wrap the circumference of the stone in a compressive band so as to press any fault lines together and prevent the stone from cracking or splitting apart. Such bands can be conventional steel bands or clamps that can be tightened by the rotation of a screw, a gear-type device, or the like.

(b) Catalytic Converter

In yet other preferred embodiments, a system of the present disclosure may be used to decontaminate a combustion gas from an internal combustion engine. An internal combustion engine may be any conventional engine including, but not limited to, a two-stroke engine, a four-stroke engine, a six-stroke engine, a diesel engine, a turboprop engine, an Atkinson cycle engine, a Miller cycle engine, a Wankel engine, a gas turbine, or a jet engine. One preferred embodiment of the present invention is a system that may be used to decontaminate combustion gas from a diesel or gas internal combustion engine. Diesel and gas internal combustion engines are known to produce large amounts of contaminants and particulates that may be efficiently decontaminated using a system of the disclosure.

When used to decontaminate combustion gas from an internal combustion engine, the present invention can replace or supplement the catalytic converter that is found on vehicles. As shown in FIG. 5 of the present disclosure, the catalytic converter 64 may generally comprise a rigid canister 66 having an inlet 68 and an outlet 70 for conducting combustion gas therethrough. The size and shape of a canister can and will change to accommodate volcanic rock capable of decontaminating exhaust gas and to accommodate different shapes of cars or to make them different aesthetically. A rigid canister may be the same diameter, and continuous with conduits for exhaust gas attaching to inlet and outlet of said canister. Alternatively, a rigid canister 66 may be bigger than conduits for exhaust gas attaching to inlet 68 and outlet 70 of said canister 66. Volcanic rock 72 may be disposed within said canister 66 to contact exhaust gas entering said canister. Volcanic rock 72 may be volcanic rock aggregate packed into the canister 66 of the catalytic converter 64. Preferred sizes are as described above. More preferably, the volcanic rock 72 is pebble sized, preferably having a diameter less than about 10 cm, still more preferably, less than about 9 cm, even more preferably less than about 8 cm, still more preferably less than about 7 cm, even more preferably from about 1 cm to about 7 cm, still more preferably from about 1 cm to about 6 cm. It is understood that the combustion gas needs to contact the volcanic rock 72, so there must be a sufficient amount of volcanic rock 72 placed in the canister 66 to accomplish this purpose. In preferred forms, the volcanic rock occupies from about ½ to 1/40^(th) of the volume of said canister 64. Other preferred forms of the invention have the volcanic rock occupy ⅖^(th) to 1/30^(th), 4/9^(th) to 1/27^(th), ⅓^(rd) to 1/25^(th), ⅓^(rd) to 1/20^(th), ¼^(th) to 1/15^(th), ⅕^(th) to 1/10^(th), or ⅙^(th) to ⅛^(th) of the volume of the canister 66. As with the other uses, there must also be sufficient flow to pass through the volcanic rock. If necessary, a vacuum can be placed by or after the outlet 70 to help pull the combustion gas through the system or an air current generator can move air from the inlet 68 to the outlet 70. For example, air from an air pump can be directed through tubing 74 at any point between the inlet 68 and outlet 70.

Alternatively, volcanic rock is a solid block of volcanic rock with conduits therethrough for channeling combustion gas out of combustion engine as shown in FIGS. 4 A, 4B, and 4C. Said conduits may be shaped to optimize contact of exhaust with heated volcanic rock for efficient decontamination of combustion gas. For instance, said conduits may be winding, forked, and may intertwine with one another to generate surface area for increased contact with combustion gas.

Said canister 66 may be at any distance from the internal combustion engine. Advantageously, because volcanic rock 72 can withstand elevated temperatures for extended periods of time without loss of integrity, said canister 66 may be disposed in close proximity to the internal combustion engine, thereby heating the volcanic rock 72 to temperatures that presently existing catalytic converters cannot withstand.

As with the stove discussed above, the canister of the present disclosure can include a mechanism for cleaning the volcanic rock therein, or it may provide an access door allowing the volcanic rock to be removed and cleaned or replaced. Potential mechanisms are the same as discussed above.

As with the other embodiments disclosed herein, the combustion gases generated by the combustion of the fuel need to contact the volcanic rock for an amount of time sufficient to remove pollutants from the gases. Any pollutant, including but not limited to dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof are removed from the gases. In preferred forms, the volcanic rock removes at least one, preferably at least two, more preferably at least 3, 4, or 5, still more preferably at least 6, 7, 8, 9, or 10, even more preferably at least 11, 12, 13, 14, or 15, and even more preferably 16, 17, 18, 19, or 20, and still more preferably more than 20 pollutants from the combustion gas. Most preferably, all of the pollutants are removed from the combustion gas. Rather than considering the pollutants individually, the volcanic rock can remove at least 10% of the pollutants from the combustion gas. More preferably, the volcanic rock can remove at least 20%, even more preferably at least 30%, still more preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, still more preferably at least 70%, more preferably at least 80%, even more preferably at least 90%, still more preferably at least 95%, more preferably at least 96%, even more preferably at least 98%, still more preferably at least 99%, and most preferably 100% of the pollutants in the combustion gas.

Other embodiments of the present invention include multiple layers of volcanic rock disposed in the canister. Preferably each layer includes a small gap between it and the next layer. Such a multiple layer system provides an increased opportunity for all of the combustion gases to contact volcanic rock. Again, conduits or passageways can be placed through the volcanic rock in order to facilitate airflow toward the exhaust outlet of the combustion chamber. Such multiple layer systems may find particular utility when using blocks of volcanic rock.

(c) Incinerator

In preferred embodiments, a system of the present disclosure may be used to decontaminate a combustion gas from an incinerator. An incinerator may be any conventional incinerator including, but not limited to, a rotary kiln incinerator, a fluidized bed incinerator, a liquid injection incinerator, a multiple hearth incinerator, a catalytic combustion incinerator, a waste-gas flare incinerator, or a direct-flame incinerator. Referring to FIG. 6, an incinerator 76 generally comprises a combustion chamber 82 with an inlet 78 for fuel and an outlet 80 for gas generated by the combustion of the fuel. The incinerator can further include various power generation 84 and exhaust cleaning systems 86 associated with the combustion chamber. For instance, the heat produced from combustion can be used to power a steam turbine 84 and the exhaust gases may be channeled through conduits in an incinerator for harvesting the heat energy in the exhaust and for filtration 86 of the exhaust.

When used in an incinerator 76, volcanic rock 88 may be disposed in exhaust conduits at any distance from the combustion chamber 82 to force exhaust gas to flow through heated volcanic rock prior to exiting the outlet 80. Preferably, volcanic rock 88 is disposed in a combustion chamber 82 of an incinerator 76 suspended at a predetermined distance above the incinerator fire 90 for heating volcanic rock 88. Disposing volcanic rock 88 in a combustion chamber of an incinerator also allows particulates in a combustion gas to contact heated volcanic rock 88, further catalyzing removal of particulates. Preferably, volcanic rock 88 disposed in a combustion chamber 82 is disposed in a plane entirely covering the transverse cross section of a combustion chamber 82, thereby maximizing exposure of combustion gas and particulates in the combustion chamber 82 to heated volcanic rock 88. More preferably, volcanic rock 88 is disposed in a combustion chamber of an incinerator 76 suspended at a predetermined distance above the fire 90, prior to the point of exhaust of combustion gas generated by the burning of fuel in the incinerator 76. The height of volcanic rock 88 above the fire 90 can and will vary depending on the design of the incinerator 76, the fuel being burned, and the desired flow of the gases generated by the combustion of the fuel. In general, the volcanic rock 88 will be located somewhere in the combustion chamber 82 and can even line the sides of the chamber 82. When covering the transverse cross section of the chamber 82, the volcanic rock 88 is preferably between about 6 inches to 18 feet, more preferably between about 8 inches and 15 feet, still more preferably between about 10 inches and 12 feet, even more preferably between about 1 foot and 10 feet above the height of the fire 90. The volcanic rock 88 may be disposed in an incinerator using a perforated support such as a perforated steel tray such that the gases generated from the combustion of the fuel can contact the volcanic rock.

In some embodiments, incinerators may further comprise boilers capable of using heat energy generated from fuel combustion to generate steam for energy generation. When an incinerator comprises a boiler, arrangement of incinerator, boiler, and volcanic rock may be as described below.

Similar to the embodiments discussed above, an incinerator 76 in accordance with the present disclosure can include a cleaning mechanism for the volcanic rock 88. Such a mechanism can be as described above and can include a liquid applicator, an agitator, or a way to access the volcanic rock 88 in the incinerator to remove it for cleaning or replacement.

As with the other embodiments disclosed herein, the combustion gases generated by the combustion of the fuel need to contact the volcanic rock for an amount of time sufficient to remove pollutants from the gases. Any pollutant, including but not limited to dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof are removed from the gases. In preferred forms, the volcanic rock removes at least one, preferably at least two, more preferably at least 3, 4, or 5, still more preferably at least 6, 7, 8, 9, or 10, even more preferably at least 11, 12, 13, 14, or 15, and even more preferably 16, 17, 18, 19, or 20, and still more preferably more than 20 pollutants from the combustion gas. Most preferably, all of the pollutants are removed from the combustion gas. Rather than considering the pollutants individually, the volcanic rock can remove at least 10% of the pollutants from the combustion gas. More preferably, the volcanic rock can remove at least 20%, even more preferably at least 30%, still more preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, still more preferably at least 70%, more preferably at least 80%, even more preferably at least 90%, still more preferably at least 95%, more preferably at least 96%, even more preferably at least 98%, still more preferably at least 99%, and most preferably 100% of the pollutants in the combustion gas.

Other embodiments of the present invention include multiple layers of volcanic rock disposed in the combustion chamber. Preferably each layer includes a small gap between it and the next layer. Such a multiple layer system provides an increased opportunity for all of the combustion gases to contact volcanic rock. Again, conduits or passageways can be placed through the volcanic rock in order to facilitate airflow toward the exhaust outlet of the combustion chamber. Such multiple layer systems may find particular utility when using blocks of volcanic rock.

(d) Boiler

In other preferred embodiments, a system of the present disclosure may be used to decontaminate a combustion gas from a boiler. A boiler may be any conventional boiler including, but not limited to, a pot boiler, a fire-tube boiler, a water-tube boiler, a flash boiler, a fire-tube boiler with water-tube firebox, or a sectional boiler.

In one alternative of the embodiments, a boiler is a pot boiler. In essence, a pot boiler comprises a combustion chamber disposed beneath a supply of water for producing low-pressure steam. A system of the present disclosure may be used to decontaminate a combustion gas from a pot boiler essentially as described above. In essence, volcanic rock may be disposed in a combustion chamber of a pot boiler, suspended at a predetermined distance above the fire, and before the point of exhaust of combustion gas.

In the embodiment shown in FIG. 7, a boiler is a water-tube boiler 94. A water-tube boiler 94 generally comprises a combustion chamber 96 and a water tube 97 or a bundle of water tubes connected thereto and extending from a water barrel 98 and leading to a steam chamber or drum 99. Heat generated from the burning of fuel in the combustion chamber 96 heats the water circulating in the water tubes 97 and converts it into steam which rises into the steam chamber or drum 99. As with a conventional water-tube boiler, the steam chamber or drum 99 can include a pressure relief valve 106 for safety purposes. Additionally, the water-tube boiler can include a superheater 108. The superheater permits steam including saturated steam or wet team to reenter said combustion chamber through tubes to become superheated and be converted to dry steam used in steam engines or in processes, such as steam reforming. A system of the present disclosure may be used to decontaminate a combustion gas from a boiler in the same manner as described elsewhere herein. Generally, volcanic rock may be disposed in a combustion chamber 96 of a water-tube boiler 94 suspended at a predetermined distance above the fire 102, and prior to the point of exhaust 104 of combustion gas.

In one alternative of the embodiments, volcanic rock 100 is volcanic rock aggregate and in another embodiment, the volcanic rock 100 can be a block that is cut to a desired size and shape. Volcanic rock aggregate may or may not contact steam generating tubes in a combustion chamber of a water-tube boiler. For instance, volcanic rock may be disposed above water and steam tubes in combustion chamber of boiler at the point of exhaust of combustion gas as shown in FIG. 7. In a preferred alternative of the embodiments, the volcanic rock 100 contacts steam generating tubes in a water-tube boiler. As shown in FIG. 8, when the volcanic rock is in block form 110, steam tubes or fire-tubes 112 can extend through the block of volcanic rock 110 such that they are completely surrounded by the volcanic rock 110. Such an orientation enhances the efficient heat transfer from the combustion to the water or steam inside the tubes 112. A similar configuration is shown in FIG. 9 where the volcanic rock 114 is in aggregate form and supported by or positioned on a perforated grate, such as a steel grate. Steam tubes 118 extend through the pile of volcanic rock 114, thereby enhancing the heat transfer from the combustion to the water or steam inside the tubes 118. Preferably, the volcanic rock aggregate 114 contacts and completely surrounds the steam generating tubes 118 in the water-tube boiler, enhancing heat transfer from combustion and increasing efficiency of boiler.

In the further embodiment illustrated in FIG. 10, a boiler 120 includes water or steam tubes 122 that are positioned on the outside of the boiler 120. Preferably, such tubes 122 contact the outside surface of the boiler which is made of a material that can efficiently transfer heat to the tubes 122 and thereby heat the liquid therein.

As with the other embodiments disclosed herein, the combustion gases generated by the combustion of the fuel need to contact the volcanic rock for an amount of time sufficient to remove pollutants from the gases. Any pollutant, including but not limited to dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof are removed from the gases. In preferred forms, the volcanic rock removes at least one, preferably at least two, more preferably at least 3, 4, or 5, still more preferably at least 6, 7, 8, 9, or 10, even more preferably at least 11, 12, 13, 14, or 15, and even more preferably 16, 17, 18, 19, or 20, and still more preferably more than 20 pollutants from the combustion gas. Most preferably, all of the pollutants are removed from the combustion gas. Rather than considering the pollutants individually, the volcanic rock can remove at least 10% of the pollutants from the combustion gas. More preferably, the volcanic rock can remove at least 20%, even more preferably at least 30%, still more preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, still more preferably at least 70%, more preferably at least 80%, even more preferably at least 90%, still more preferably at least 95%, more preferably at least 96%, even more preferably at least 98%, still more preferably at least 99%, and most preferably 100% of the pollutants in the combustion gas.

Other embodiments of the present invention include multiple layers of volcanic rock disposed in the combustion chamber. Preferably each layer includes a small gap between it and the next layer. Such a multiple layer system provides an increased opportunity for all of the combustion gases to contact volcanic rock. Again, conduits or passageways can be placed through the volcanic rock in order to facilitate airflow toward the exhaust outlet of the combustion chamber. Such multiple layer systems may find particular utility when using blocks of volcanic rock.

EXAMPLES

The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

Example 1 Crude Analysis of Flue Gas

The purpose of this experiment was to analyze flue gas samples obtained from a stove built by the inventors using volcanic material (lava rock), as a filtration medium for exhaust gases resulting from the combustion of tires and wood. The wood stove was substantially similar to the stove depicted in FIG. 1.

Instrumentation and Materials:

A hole was drilled into the flue pipe of the stove at approximately 12-15 inches above the stove. Steel tubing similar to that used for automotive brake lines was inserted into the hole and a 30 mL sterile, latex-free BD Syringe with Luer-Lok tip was butted up against the tubing and filled with gases exhausting from the combustion chamber. The gas was then dispensed from the syringe into a short path gas transmission cell (Pike Technologies, Madison, Wis.). The syringe was filled three times and used to flush the cell of atmospheric air. The syringe was then filled three times and injected into the cell for spectral analysis using a Shimadzu IRAffinity-1 Fourier Transform Infrared Spectrophotometer.

Results:

The spectra of exhaust gases from mixed fuels including plastics and tires (FIG. 11) and wood (FIG. 12) show that exhaust gas from the stove mainly comprised water vapor and CO₂. 

What is claimed is:
 1. A device for removing at least one pollutant from a combustion gas comprising: A combustion chamber having an inside and an outside, said inside including a heat source therein, said heat source generating a combustion gas that includes pollutants therein; An exhaust passageway having an entrance inside said combustion chamber and an exit outside said combustion chamber and connecting said combustion chamber inside with said combustion chamber outside; A quantity of volcanic rock inside said combustion chamber, said volcanic rock being positioned between said heat source and said exhaust passageway; wherein said combustion gas contacts said volcanic rock prior to entering said exhaust passageway thereby removing at least one pollutant from said combustion gas prior to entering said exhaust passageway and exiting the inside of said combustion chamber.
 2. The device of claim 1, wherein said pollutants are selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof.
 3. The device of claim 1, wherein said combustion chamber is located in a device selected from the group consisting of a furnace, stove, incinerator, boiler, automotive exhaust system, and combinations thereof.
 4. The device of claim 1, wherein said heat source uses a fuel selected from the group consisting of liquefied fuel, gaseous fuel, contaminating fuel, wood, charcoal, peat, coal, hexamine fuel tablets, pellets made from wood, corn, wheat, rye, or other plants, and combinations thereof.
 5. The device of claim 1, wherein said volcanic rock is in a form selected from the group consisting of chunks, blocks, and combinations thereof.
 6. The device of claim 1, wherein said quantity of volcanic rocks occupies from about ⅓rd to 1/25th of the volume of said combustion chamber.
 7. The device of claim 1, wherein said quantity of volcanic rocks is positioned in said combustion chamber such that there is an empty space between the top of said quantity of volcanic rocks and the entrance to the exhaust passageway.
 8. The device of claim 1, further comprising a cleaning mechanism for cleaning said quantity of volcanic rocks.
 9. A system for removing at least one pollutant from the exhaust of an internal combustion engine comprising: An internal combustion engine having a combustion chamber therein, said combustion chamber including a fuel burning area which generates exhaust when a fuel is being burned; An exhaust port having a first end in proximity to said fuel burning area and a second end in communication with said first end, wherein said second end is in proximity to the environment outside said internal combustion engine; A quantity of volcanic rock disposed between said fuel burning area and said second end of said exhaust port.
 10. The system of claim 9, further comprising a canister in communication with said exhaust port, said canister having a diameter greater than the diameter of said exhaust port.
 11. The system of claim 10, wherein said volcanic rock is disposed within said canister.
 12. The system of claim 9, wherein said volcanic rock is disposed before said first end of said exhaust port.
 13. The system of claim 9, wherein said pollutant is selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof.
 14. The system of claim 9, wherein said fuel is selected from the group consisting of liquefied fuel and gaseous fuel.
 15. The system of claim 9, wherein said volcanic rock is in a form selected from the group consisting of chunks, blocks, and combinations thereof.
 16. The system of claim 9, wherein said quantity of volcanic rock occupies from about ⅓rd to 1/25th of the volume of said combustion chamber.
 17. A method of decontaminating polluted combustion gas comprising the step of: contacting said polluted combustion gas with volcanic rock for a time sufficient to remove at least one pollutant from said polluted combustion gas.
 18. The method of claim 17, wherein said pollutant is selected from the group consisting of dioxins, styrene gas, polychlorinated biphenyls, mercury, furans, polycyclic aromatic hydrocarbons, formaldehyde, hexachlorobenzene, volatile organic compounds, hydrochloric acid, carbon monoxide, benzo(a)pyrene, sulfur oxides, benzene, hexavalent chromium, lead, hydrocarbons from unburned fuel, nitrogen oxides, nitric acid, ozone, soot, diesel particulate matter, heavy metals, methane, and combinations thereof.
 19. The method of claim 17, wherein said polluted combustion gas is formed in the combustion chamber of a device selected from the group consisting of a furnace, stove, incinerator, boiler, automotive exhaust system, and combinations thereof.
 20. The method of claim 17, wherein said polluted combustion gas is formed from the combustion of a fuel selected from the group consisting of liquefied fuel, gaseous fuel, contaminating fuel, wood, charcoal, peat, coal, hexamine fuel tablets, pellets made from wood, corn, wheat, rye, or other plants, and combinations thereof.
 21. The method of claim 17, wherein said volcanic rock is in a form selected from the group consisting of chunks, blocks, and combinations thereof.
 22. The method of claim 17, wherein said volcanic rock occupies from about ⅓rd to 1/25th of the volume of said combustion chamber.
 23. The method of claim 17, further comprising the step of cleaning said volcanic rock.
 24. The method of claim 23, wherein said cleaning is effected in said combustion chamber. 